THE EFFECT OF AGGREGATE CHARACTERISTICS ON THE PERFORMANCE OF PORTLAND CEMENT CONCRETE

Aggregate characteristics of shape, texture and grading have a significant effect on the performance of concrete. Interest in high performance concrete and concrete with high fines has emphasized the importance of improving the aggregate particle distribution. The purpose of this project is to develop a mixture proportioning method based on the optimization of the aggregates and adequate test methods to predict performance of aggregates. As part of this project, the results of two studies evaluating the effect of high fines in mortar and concrete are presented. In the first study, two groups of aggregates were used to make mortar and concrete with given water-cement ratios and cement factors. One of the groups had no added minus No. 200 while the second group had 15% of minus 200. Except for the minus 200 fraction, all the aggregates were recombined so they had the same gradation. Two superplasticizers and a low-range-water-reducer were used in some mixtures to evaluate their effect. In the second study chemical and mineral admixtures were used in mixtures with no microfines and with different amounts of added microfines. Two cases were considered: crushed sand with different amounts (5, 10 and 15%) of microfines and natural sand with no microfines which served as control. Mixtures were designed for a constant water-cement ratio of 0.50 and a target slump of 5 in. A water reducer was used for half of the mixtures and a superplasticizer for the other half. For case II, the same aggregates of case I were used. For each microfines content, partial replacements of cement were made with class C fly ash, class F fly ash, and silica fume. A constant water/cement ratio of 0.53 and a target slump of 5 in were used. Additionally, a fixed dosage of air entrainment agent and varying amounts of superplasticizer were used in order to reach the target slump.

• Supplemental Notes:
  • Full conference proceedings available on CD-ROM.
• Corporate Authors:

  University of Texas, Austin

  International Center for Aggregates Research, 3208 Red River
  Austin, TX  United States  78705-2650

  Texas A&M University, College Station

  Faculty Exchange Box H
  College Station, TX  United States  77843
• Authors:
  • Quiroga, P
  • Whitthoft, S
  • Paik, S
  • Fowler, D W
• Conference:
  • International Center for Aggregates Research 9th Annual Symposium: Aggregates - Concrete, Bases and Fines
  • Location: Austin, Texas
  • Date: 2001-4-22 to 2001-4-25
• Publication Date: 2001

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 23p

Subject/Index Terms

• TRT Terms: Admixtures; Aggregates; Aggregates by gradation; Aggregates by shape and surface texture; Air entraining agents; Chemicals; Crushed aggregates; Fly ash; High performance concrete; Minerals; Mixtures; Mortar; Optimization; Particles; Performance; Portland cement concrete; Proportioning; Sand; Silica fume; Superplasticizers; Test procedures; Water cement ratio; Water reducing agents
• Uncontrolled Terms: High fines concrete; Microfines
• Subject Areas: Geotechnology; Highways; Materials; I32: Concrete; I36: Aggregates;

Filing Info

• Accession Number: 00983565
• Record Type: Publication
• Report/Paper Numbers: Final Draft
• Files: TRIS
• Created Date: Dec 24 2004 12:00AM